Kite boarding, sometimes also referred to as kite surfing, is an extreme sport whereby a person uses a kite, generally having a “C” or modified “C” shape. Such shape, also termed “a leading edge inflatable kite”, is created by using a hand or electrically operated pump to inflate an elastomeric bladder contained within a protective cover material forming the kite's leading edge. The kite's leading edge, which forms a rigid C-shaped 10-20 cm diameter round tube when inflated, usually has one or more orthogonally aligned abutting struts, which structure supports the fabric material forming the kite canopy.
Besides water-based kite boarding, kites are also used on land where the rider stands on a skateboard type device (with wheels) travelling on, for example, packed sand, or sitting in a device with wheels for travel over a hard surface. Recently, kites have also been deployed by snow boarders for use over snow-covered areas.
U.S. Pat. No. 4,708,078 by Legaignoux, et al. teaches the first use of a kite design that can be re-launched from the water surface, which key innovation spurred the sport of kite boarding. Modern prior art kites are attached to 4 (or 5) lines, which lines are generally 10-30 meters in length, and are also attached (tethered) to the kite rider, who is wearing a special harness, allowing the kite rider, while standing on a surfboard-like device, to be pulled along the surface of the water due to wind powering the kite.
A key aspect of kiting is achieving proper inflation of the kite's leading edge and strut bladders, which bladders are generally comprised of air-impermeable polyurethane film, about 100 microns thick, containing inflate and deflate valves. Said bladders are covered with an abrasion-resistant and tear-resistant protective cover material. During use, the kite's leading edge and strut bladders are inflated to about 5-10 psi (34-69 kPa) above ambient atmospheric pressure. Kite sizes are based on the square area of the kite's canopy, and range from 5 m2 to over 20 m2. To maintain optimum kite rigidity, the kite's leading edge and struts are generally pumped to the same pressure. Smaller kites, such as 5 m2, are pressurized to about 10 psi (69 kPa), whereas larger kites, such as 20 m2, are pressurized to about 5 psi (34 kPa). The leading edge bladder and struts can be inflated simultaneously, or separately.
U.S. Pat. No. 7,140,576 B2 to Logosz discloses a method for pumping the leading edge kite bladder and struts simultaneously, and then closing off the struts from the leading edge, which two components are connected by a rubber tube. A clamp over the rubber tube is used to open or close the air passage between the leading edge bladder and the strut bladders. Separately sealed struts and leading edge provide floatation redundancy in case of leaks in the leading edge, or in one or more of the struts.
It is estimated that more than half of kiters “under-inflate” their kites, especially beginners, and intermediate level kiters. Kites can also slowly deflate without detection due to pinhole leaks in the leading edge bladder, or struts (if not sealed off). Under-inflated kites become “floppy” and can easily invert during use, potentially tangling lines around the kite. Also, an under-inflated kite can lose its aerodynamic shape, and thus reduce the power necessary to hold the kiter above water. Over-inflated kites can cause the protective cover material (also referred to as the leading edge tube) enclosing the kite bladder to rupture. This is especially true if the kite hits the water surface with force, causing a sudden, sharp increase in air-pressure within the leading edge bladder. Also, the protective cover material can rupture if the kite is exposed to heat, induced, for example, by leaving the kite exposed to direct sunlight.